Fuel-injection device for internal-combustion engines



Feb. l 1927.

F. ROCHEFORT FUEL INJECTION DEVICE FOR4 INTERNAL GOMBUSTION ENGINES Filed Dec. 20. 1924 Patent Feb. 1, 1927.

' y. i; D

FItANQOIS ROCHIJIEOBJI, OF PARIS,.FRANCE.

runL-mne'rron DEVICE Fon INTEBNAL-COMBUSTION Encinas.

Application led December 20, 1924, SerialNo. 757,170, and inrFrance December 28, 1923.

yMy present inventionl relates to fuel injection devices for internalicombustion engines, of. the type in which the pressure of the liquid itself is utilized for lifing from its seat the fuel injection valve or the like, which forms likewise the valve forthe compressed' air or vas serving for the diffusion of the liquid fuel, by the pressure of the liquid fuel acting upon a piston connected to the said Valve.

My invention more particularly relates to` and shownin my application for United States Letters Patent, filed April 30, 1923,

Serial No. 635,788, in which thepliquid fuelr is admittedv by a passage of very small sectional area, between the cylindrical external surface of Athis piston and the cylindrical bore in which the said piston is displaceable, so as to obtain a constant sectional area of passage for the liquid fuel, with a View to ensure its mechanical lamination before its mixture with the difusion air or gas under pressure, whatever be the quantity of liquid fuel admitted,the said lamination of the liquid fuel being thus maintained whatever be the lift of the piston.

According to my present-invention, this passage of constant sectional area for the liquid fuel consists of an accurately gauged annular clearance space of small-.and conv stant cross sectional area rprovided between the cylindrical external surface of the piston and its cylindrical lodgment in the valvecasing.

- The accompanying drawing represents by f,

way of example one form of construction in accordance with my invention.

Fig. 1 is a vertical axial section through the injection device, and

Fig. 2 a horizontal section on line 2-2 of Fig. 1.

As shown, a is the body of the injector, adapted to besecured by a screwthread to fthe cylinder head b of the engine. The body a receives on one side the end c of the compressed air supply pipe, and, on the otherl In the valve casing e is arranged a valve body consisting of a. fiat-seated valve Z, fast,

with a cylindrical member or piston m, located in a cylindrical bore c provided inthe valve easing e. The external diameter of this piston m andthe internal diameter of the ybore k are such as to provide an acculrately gauged annular clearance between the the valve and, at the other end, upon a tubular plug '0, screwed 4in the member 1 and which serves at the same time as a stop for v' the valve-stem'Z1 for the purpose of limiting the lift of the valve Z. Notches 01, provided in the lower end of the tubular plug o, allow the compressed air, admitted through c and an opening c1 in the valve casing e, always to exert its pressure upon the whole surfaceof the valve Z, so as to ensure, together with the spring n, rapid closing of'this valve.

Liquid fuel is supplied from oZ through the port. Z1 beneath Ythe piston m. Under the pressure of the fuel delivered by the injection pump (not shown), the, piston fm is lifted, raising with it the valve Z which is raised from its. flat seating e1; the liquid fuel is discharged through the very small but accurately calibrated clearance provided between the cylindrical piston m and bore,l 7c, and passes, in tlieform of a thin film, be'

tween the flat JValve Z and its seat el; the compressed4 air, at the same time admitted through c 01, and the space between the valve l Z and its seat c1, in the form of a thin film,

meets with the said fuel and mixes therewith in an annular chamber, consisting of a circular groove e2 recessed 1n the seat e1 of the valve, between the inlets of air and fuel controlled by the said valve. The mixture thus formed passes through convergent-divergent nozzle e3, arranged symmetrically to the axis of tlievalve and opening into the annular mixing chamber c2; these nozzlesieS discharge into the engine cylinder, so

as to increase the speed of the mixture and to distribute'this fuel mixture upon a greater area in the engine cylinder.

By the above described arrangement, there is obtained a thorough atomization of the liquid fuel and diffusion air or gas and a thorough mixture of the same.

What claim is:

lll)

1. A fuel injection device for internal comg f i 111316,335

bustion engines, comprising a body, separate inlet passages in said body for fuel and gas supplied under pressure, a single Valve member arranged to control passage through the body of both fuel and gas under pressure by t its displacement relatively t'o the body, a vpiston connected 'to said valve member, a vcylindrical bore in the body for receiving the piston, the piston having an external diameterslightly less than the internal diameter of the bore in the body so as to provide an accurately gauged annular clearance space of small and constant cross sectional area between the cylindrical external surface of the piston andthe cylindrical bore in the body member, means establishing communication between said fuel inlet and said bore whereby said piston together with the valve member is moved relatively to said body through a pressure exerted on said piston by the fuel to thus allow passage of fuel and gas under pressure through the body, and means for moving the valve member with the associated piston in the opposite direction for cutting olf the flow of fuel and gas under pressure.

2. A fuel injection device for i'nternal combustion engines, comprising a body, separate inlet' passages'in said body for fuel and gas supplied under pressure, a valve seat, a single valve" member closing on the seat and arranged to control passage'through the body of both fuel and gas under pressure by its displacement relatively to the body, a piston connected to said valve member, a V cylindrical bore in thebody for receiving the piston, the piston having an externaludiameter slightly less than the internal diameter ofthe bore in the body so as to provide an accurately gauged annular clearance space 49 of small and constant cross sectional area be tween the cylindrical external surface of the piston and the cylindrical bore in the body member, said body Abeing formed with an annular mixing chamber for the liquid-fuel and gas under pressure positioned in the -valve seat communicating with the engine cylinder, means establishing communication between said fuel inlet and said bore whereby said piston together with the valve mem- 50 ber is moved relatively to said body through pressure exerted on said piston by the fuel to thus allow passage of fuel and gas under pressure through thebody, and means for moving the valve member with the associated piston in the oppositel direction for cutting oil' the flow of fuel and gas under pressureT A fuel injection device for internal-combustion engines, comprising a body, separate inlet passages in said body for the fuel' and 6 gas supplied under pressure, a,I valve memberw arranged to control passage through the body of both fuel and gas under pressure by its ,displacement relatively to the body, a piston vconnected to said valve member, a cylindrical bore in"the'body for receiving the pist-on, the piston having an external diameterslightly less than the internal diameter of the bore in the body member so as to provide an accurately gauged annular clearancespace between the cylindrical external surf face of the piston and the cylindrical bore in the body, thevalve member having a flat portion for controlling both the flow of the gas 'under pressurel and of the liquid fuel passing through the accurately gauged an-f nular clearance space, means estabhshmg bustion engines, comprising a body, separate inlet passages in said body for the fuel andl .gas supplied under pressure, a valve seat,

a valve member closing on the seat and ar ranged to control passage of both fuel and gas under pressure through the body by its `displacement relatively to the body, a piston 'connected to said valve membera cylindrical bore in the body for receiving the piston,

the piston having an external diameter slightly less than the internal diameter of the bore in the body soas to provide an accurately gauged annular clearance space between the cylindrical `external surface of the piston and the cylindrical bore in the body, means establishing 'communication between said fuel inlet and said bore whereby said piston together with the valve member is moved relatively to said body through pressure exertedon said piston by the 'fuel to thus allow passage of fuel and gas under pressure through the body, and means for moving the valve member with the associated piston in the opposite direction for cutting off the How of fuel and gas under pressure, and convergent-divergent body outlet nozzles arranged symmetrically of the axis `of the. valve member, opening into the'valve seat, and arranged to discharge directly into an engine cylinder. y

In testimony whereof I have signed my name to this specification.

FRAN QOIS RGCHEFORT. 

